The present invention relates to a berry stripping machine for grapes, and more particularly to a berry stripping machine of the type that includes a machine housing and an open ended berry stripping cylinder that is mounted in the machine housing so as to be rotatable about a horizontal axis, with one of the open ends of the berry stripping cylinder serving as an entrance opening for the grapes and with the other open end serving as an exit opening for the pedicels stripped from the berries. A berry stripping machine of this type may possibly also include crushing rollers that are disposed below and parallel to the berry stripping cylinder to receive berries leaving the berry stripping cylinder through its berry stripping openings, with the crushing roller being followed at the bottom by a housing opening. A berry stripping machine of this type further includes a spiked roller disposed within the berry stripping cylinder essentially concentric therewith and rotatably mounted in the machine housing. The berry stripping cylinder and the spiked roller may be driven to rotate in the same direction or in opposite directions at different speeds, so that spiked roller revolves faster than the berry stripping cylinder. Finally, a machine of this type includes a fill funnel for the grapes. The full funnel is open at the top and connected upstream of the intake opening of the berry stripping cylinder in the machine housing.
Such a berry stripping machine serves to separate the berries from the grape bunches, with the berries being freed from the pedicels and stems and with the pedicels leaving the machine without having any berries attached to them. In this connection, demands are increasingly made toward inflicting as little damage as possible to the berries. It is also very undesirable for the berries to still be attached to pieces of pedicels or stems.
In the prior art berry stripping machines, the berry stripping cylinder and the spiked roller have a common drive, with the drive connections being designed so that berry stripping cylinder and spiked roller operate at a constant speed ratio. The drive may here be regulated over a certain range. This is permits the throughput quantity of the machine to be adjusted to the availability of different quantities of grapes and/or grape species. It also permits grapes that are overripe or afflicted with botrytis to be treated more gently in the machine for example.
The drawback is that the control range is relatively limited, which means that the machine is not able to be controlled very far downward. The very low number of revolutions of the berry stripping cylinder that then results brings about the consequence that the berries will no longer be separated to a sufficient degree, so that pedicels which leave the machine carry too many berries.
Because of these limits in the reduction of velocity, the machine cannot be operated below capacity, that is, with small available quantities of grapes, since then the length of the berry stripping cylinder is no longer utilized fully. Rather, with below capacity operation, the berry stripping work may already be completed after passage through one third of the berry stripping cylinder, for example, so that only the bared pedicels are processed through the remaining two thirds of the machine. This results in a relatively large percentage of small pedicels or pedicel pieces among the berries, which is absolutely undesirable.